JPS5839471B2 - High-pressure degassing and gasification method for crude lignite - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method of high-pressure degassing and gasification of coarse lignite, especially soft lignite, in which the drying of lignite is directly combined with the high-pressure degassing and gasification process, and the energy demand for the drying process is reduced. Concerning what is the minimum.

The drying is carried out very carefully so that even granular coarse lignite and soft lignite with a high water content can be directly charged without particle disintegration having a negative effect on the degassing and casing process.

By application of the method of the present invention, the degree of carbonization (Mkoh-1u
Granular lignite with a low ngs grade can be gasified under pressure in a fixed or fluidized bed to produce fuel with low granular smoke in some cases.

It is already known to use lignite, especially soft lignite, for high-pressure gasification in fixed or fluidized beds.

When lignite is used in the form of briquettes in fixed bed high pressure gasification,
Previously known solutions require expensive pretreatment of the briquettes through particle treatment, drying and pressing.

In the high-pressure gasification process with high specific capacity, it became clear that the briquettes could not withstand the strong heat load, and they collapsed during final drying and degassing in the gas reactor, resulting in extremely high levels of dust being carried out by the high-pressure gasification crude gas. It is tied to

In addition, soft lignite particles dried in a tube dryer outside the gasifier have already been used in the high-pressure gasification process.

However, the high-pressure gasification process with high specific capacity and without a high degree of dust removal has hitherto been possible only when using dry particles of hard lignite and when using coal.

On the other hand, with soft lignite particles dried in tube dryers, acceptable dust emissions associated with the crude gas can only be achieved at low specific capacities for gasification.

In order to increase gasification capacity, soft lignite is currently predominantly used in the form of briquettes for fixed bed gasification.

Briquetting and drying equipment requires high costs for technical equipment, operation and maintenance; o Environmental pollution due to dust is considerable.

The dry pulverized coal produced places the entire system at constant risk of explosion.

Significant wear and tear occurs during dry fuel transport.

Moreover, the energy demand for drying is high due to evaporative drying and the associated waste heat losses.

Already in the past, several proposals were made that were supposed to eliminate or reduce the disadvantages associated with the use of soft lignite.

Therefore, in East German Patent No. 26,392 it was proposed to drizzle the gasified material intensively with gas water before and/or during high-pressure gasification in order to lower the temperature of the gas escaping from the fuel bed.

East German Patent No. 38,791 describes a method in which only a portion of the hot gasified material is used for degassing and drying the fuel, and the remaining gas is drawn off separately.

A similar proposal to the above is also presented in East German Patent No. 119814.

East German Patent No. Cl0J 205413 proposes adjusting the amount of crude gas for final drying and degassing in such a way that a predetermined heating rate appears in a specific temperature range and very careful preliminary drying is carried out. There is.

East German Patents No. 121,796 and No. 120,043 recommend increasing the moisture content of the fuel used to 20-24% for briquettes and 457o for dry coal blocks.

The above proposals have so far not been introduced into practice.

While it is true that fuel decay in the high-pressure gasification reactor can be limited to a greater or lesser extent by their implementation, this is also associated with additional process-technical disadvantages and an increased burden.

These known proposals are based on the use of briquettes or convection-dried charcoal particles, but these suffer from the drawback of insufficient durability during high-pressure gasification.

Even if the equipment, energy, and work required to manufacture these products may require high costs, this does not change the situation.

For example, water K evaporates just to evaporate water from charcoal.
A heat amount of 3100-3300 KJ is required per p.

Hard brown coal is difficult to briquette.

Based on this knowledge, about 50 years ago, a drying method for hard lignite that made it much easier to lump was introduced into practice.

It was first described in the old German Patent No. 466,617 and is also known as the Fleissner process or high-pressure steaming process, named after its inventor Nagisa.

In this method, coal is heated using saturated steam under high pressure and water cannot evaporate.

Due to the contraction that occurs during heating of the charcoal and the separated CO2, some of the water is driven off in a fluid state.

This results in a reduced energy demand for water separation and a much more uniform heating and shrinkage of the particles since the separated water does not constantly remove transferred heat from the charcoal particles as in the case of evaporative drying. .

A series of proposals aimed at embodying and improving the same were presented following the original method described.

Therefore, the old German patent no. 520369 (in which hot water is used as a cooking agent instead of steam),
No. 021 (in which steam is superheated and used), also No. 583907, West German Patent No. 1049 and No. 118
No. 9465, Austria Patent No. 185349, No. 1
The methods described in eg No. 90490 and No. 244 were essentially aimed at improving thermoeconomics.

The inventions on which German patents Nos. 1,201,254 and 1,243,109 are based sought to embody a continuous process.

However, the technical burden for this is extremely heavy, and so far the continuous method has not been successful in practice.

Is the advantage of coal high-pressure steaming method in separated water? 1400-1 per
Low energy consumption of 700KJ and careful drying of charcoal.

Compared to convection drying, this method has the disadvantage of requiring high-pressure steam for drying.

During depressurization of the high-pressure steamed charcoal, some water evaporates under reduced pressure and under pressureless conditions.

This process inevitably leads to a certain degree of water content and damage to the charcoal particles, even if the drying force is lower than in convective drying.

After depressurization, water can be reabsorbed to a small extent by the charcoal.

The high-pressure steaming method has been introduced into practice when hard brown coal and brown coal with a high lignite content are used.

It has already been done to dry lignite in advance using steam in a high-pressure steamer, or to charge lignite with a high bunite content into a high-pressure gasifier and gasify it in a fixed bed.

In the case of high-pressure steaming of brittle soft lignite that can be made into briquettes, there is a concern that excessive slurry will be generated.

It is true that attempts were made to steam this kind of soft lignite, but
The main purpose was to use the dried lignite for briquettes or to produce yellow phosphorus as fuel.

In this case, it is not possible to dehydrate lignite to less than 30% without spending extra money, and the suitability of lignite for browning is often deteriorated by high-pressure steaming.

The high moisture content after drying limits the economic distance for transport compared to briquettes.

In order to utilize waste heat rationally, the high-pressure steaming method requires several interconnected high-pressure vessels and many connecting pipes.

Dehydrated brown coal must be cooled after steaming.

Discontinuous operation further increases the mechanical engineering burden.

The generated dust contaminates the environment and poses a danger of pulverized coal explosion.

It is therefore an object of the present invention to integrate the drying of crude lignite directly into a high-pressure decasing and gasification process, thus achieving a very satisfactory drying of lignite, especially all soft lignite.

The purpose of the present invention is to broadly reduce thermal energy demand, equipment technical burden, and operational burden.

The present invention is based on the task of avoiding the above-mentioned drawbacks and embodying the object of the invention.

In the case of high-pressure gasification of lignite, especially soft lignite, the high degree of dust formation in the high-pressure gasification raw gas has proven to be particularly disadvantageous, as already mentioned.

Recent research suggests that the causes of briquette collapse are as follows.

The briquette bond is crucially maintained by the cohesive forces caused by the water contained in the drying coal.

After the water has evaporated, the remaining bond strength results in a briquette bond that is still slightly loose and extremely wear-resistant.

As is known, gasification briquettes made by pressing coarse dry coal are particularly easy to disintegrate under high heat loads.

Besides, briquettes are made at a temperature of about 303-313 52
3-773°C into a gasification reactor.

This thermal shock leads to uneven heating of the briquettes.

The outer layer of the briquette dries faster and therefore contracts more strongly, creating stresses that promote collapse.

The dry charcoal particles within the briquette bond also vary in water content, the higher the average water content.

During the drying of the briquettes in the gasification reactor, the strength of the shrinkage of these particles therefore varies, leading at the same time to a strong relaxation of the briquette structure.

The causes of the disintegration of dry coal particles, especially soft brown coal, are said to be as follows.

Drying of soft lignite particles is carried out by convection drying, often by evaporation of water in a pre-dryer.

This evaporation begins in the outer layers of the particle and occurs only after a significant delay in the center.

The result is that the difference in water content between the shell and the center of the dried finished particles is in some cases greater than 30%.

As a result of the resulting contraction of the outer shell, which is larger than the center, the outer shell loosens and is extremely susceptible to wear.

A large amount of water vapor generated during drying is prevented from flowing out by the charcoal in the center, and the expanding force strongly seeks a free path, partially destroying the particle structure.

These particles are about 303-313 on the way to the generator device
Cool to K.

Moreover, the coal particles dried by convection drying must be cooled to avoid auto-ignition of the lignite.

These low-temperature charcoal particles are instantly converted into 523-77 in the generator.
exposed to temperatures of 3.

Until the boiling point of water is reached inside the particles, a shockingly strong shrinkage process takes place, starting from the particle shell to the core, which further destroys the lignite particles, which have already been weakened in the preceding drying device.

When using coal and hard lignite for high-pressure gasification, these described phenomena are limited to no or only a small amount due to the already existing shrinkage of these lignites (carbonization) and the associated low water content. only appears.

The direct method-technical combination of high-pressure steaming and high-pressure gasification is the most harmonious combination in coal reforming method technology and largely eliminates the above-mentioned deficiencies associated with known technical solutions. Conventionally, it has not been recognized that this is possible.

According to the present invention, this problem is solved as follows.

Water content 55- for high-pressure degassing and casing processes
60% granular coarse lignite, especially soft lignite, is pressurized in a known manner from a bunker in a coal box chamber and then brought to a pressure as close as possible to the same pressure as in the degassing and gasification chamber, but preferably 2 MPa.
Place in a steaming chamber at a pressure of MP a.

In the steaming chamber, the crude lignite is dehydrated and carbonized under high pressure using a steaming agent, preferably saturated steam.

The hot lignite thus predried is then entered into a degassing/gasification chamber, preferably without vacuum but never to a pressure of IMPa, and preferably without cooling, but without cooling to a temperature of 423 K.

Due to the high heat capacity of the lignite that has been predehydrated by high-pressure steaming, it is further carefully dried in a degassing and gasification chamber and subsequently subjected to degassing and gasification.

High-pressure steaming of soft brown coal produces almost no pulverized coal, and only a portion of the coarse grains disintegrate into medium-sized grains.

However, it has been found that this type of disintegration phenomenon is unlikely to adversely affect the high pressure degassing/gasification process, especially since the dehydrated particles are relatively resistant to abrasion.

The water dripping from the lignite during high-pressure steaming removes fines from the lignite, which are usually separated continuously in the high-pressure steaming chamber.

This cleaning effect can be enhanced by spreading hot steaming water, which is returned to circulation, over the lignite pile in the steaming chamber.

The continuous consumption of fuel in the degassing and gasification chamber also allows continuous charging of predried lignite.

The steam used for high-pressure steaming is saturated at the selected working pressure and placed above the brown coal pile in the high-pressure steaming chamber so that a small amount of residual steam always flows into the descaling and gasification chamber together with the gases generated during carbonization of the brown coal. Introduce it in a suitable amount.

The steam can also be slightly superheated and introduced into the gasification chamber.

It was confirmed that most of the water in lignite, especially soft lignite, is already separated at the early stage of steaming, and there is no need to continue high-pressure steaming until the residual water is released at the relevant pressure.

The lignite, which has been pre-dehydrated and heated in this way, can be used for stone wire degassing and
It can withstand the load of finishing drying and heating in the gasification chamber without major failure.

In that case, the important thing is that the crude lignite is evenly and well heated to a temperature above the boiling point under the operating conditions, but at least 423 K, and the shrinkage phenomenon proceeds evenly, provided that the lignite reaches the degassing/gasification chamber. Most of it has already been completed.

Even if the lignite has a high moisture content, for example 35-40%, this is not a major drawback.

The generated water vapor occupies only a small portion of the volume at atmospheric pressure during final drying in the degassing/gasification chamber, and can flow through the interior of the lignite without loosening its structure.

If the temperature of the particles is between 423 and the boiling point corresponding to the chosen working pressure, the movement of water from the center of the particles to the shell takes place almost in liquid form as a continuation of the cooking process.

Since the pre-dried lignite reaches the degassing/gasification chamber without cooling or contact with air, the particle surface remains plastic without oxidation or hardening.

Therefore, it is not difficult for water vapor to escape during final drying.

Reabsorption of water cannot occur. The heat brought into the degassing/gasification chamber by the high-temperature charcoal that has been steamed under high pressure is, for example,
When using briquettes with 5-40% lignite, the normal moisture content is 2.
This is sufficient to finish drying to 0%, ie, without additional heat removal from the degassing/gasification chamber.

This effect, which has not been considered in the past, is caused by careful final drying of lignite pretreated from high-pressure steaming I in a degassing and gasification chamber.

The incomplete dehydration of the lignite during high-pressure steaming makes it possible to shorten the steaming time and thus at the same time to downsize the steaming chamber.

In addition, it was confirmed that lignite particles dehydrated under pressure were able to withstand high-pressure degassing with slight disintegration compared to briquettes, and the resulting coke had higher abrasion resistance.

However, the high-pressure dehydrated lignite particles can thereby pass through the high-pressure descaling zone to a large extent safely and be guided to the gasification zone.

The steaming water generated during high-pressure steaming is depressurized and steam generated at atmospheric pressure and, in some cases, hot water are converted into raw coal.
Used to preheat to K.

Steaming water can also be used for hot water production.

The depressurized hot water is used to transport coking coal, and the banca is used to transport the coking coal by hydraulic power.
High-pressure steaming water can also be used to transport coking coal from the coal box to a steamer located before the degassing and cassification reactor.

In the case of Houzhu, pre-steaming is already carried out using hot water.

In order to be able to keep the steaming chamber small, it is expedient to pre-treat the raw coal in the coal box chamber by a diversion of a steaming agent and/or by hot steaming water.

According to the method 1 according to the present invention, the heat demand when pre-drying the crude lignite is as follows: heating the coking coal to 363 K; when using steaming water, the heat demand for pre-drying the crude lignite is 1/2 for the water separated during high-pressure steaming.
000-1200 KJ, thus lower than a separate high pressure steamer.

This advantage arises from the fact that the high-temperature lignite in the steamer does not cause any additional waste heat loss, and the calorific value of this lignite is completely utilized in the degassing/gasification process or the waste heat utilization process of the stone line.

Since the steaming process can be operated continuously, heat loss due to steamer cooling and discontinuous steam reduction is eliminated.

The additional expenditure on equipment technology is small due to the integration of the high-pressure degassing and gasification process.

The EAL process makes it possible to combine the high-pressure steaming process and the degassing/gasification process in a correspondingly sized high-pressure vessel.

If not, charging, discharging, and CO required for high-pressure steaming equipment
2 discharge and lignite chillers are no longer needed separately due to their integration with the degassing/gasifier process.

Additional steam piping for high-pressure steaming is often not required in the degassing/gasification equipment.

This is because steam piping for gasification can be used.

High-pressure degassing and gasification vessels usually have a water jacket to protect the outer pressure-resistant jacket.

The steam generated in this water tank can be used very advantageously for high-pressure steaming in the described process.

The process according to the invention does not require additional personnel.Q: The high expenditures for separate dry charcoal preparation, which are customary in the prior art mentioned above, are avoided.

The process is extremely environmentally friendly since no escape of pulverized coal into the environment can occur.

A pulverized coal explosion cannot occur. There is no basis for concerns about increased slurry generation during high-pressure steaming of soft lignite.

Compared to the use of briquettes during high-pressure degassing and gasification, there is a 3% loss during briquetting, and a 10-15% loss due to dust removal during high-pressure gasification. Slurry will be generated.

In the process according to the invention, the slurry proportions are strongly influenced by the formation of the individual processes and do not exceed those observed when using briquettes.

The process according to the invention makes it possible to use lignite with a high ash content, which would normally be unusable due to the high degree of attrition that occurs here if a briquetting step is involved.

In the high-pressure steaming process, part of the ash and particles in which microscopic MBL is dispersed are separated together with the steaming water.

Compared to the use of currently customary high-pressure degassing and gasification lubricants, the crude lignite treated according to the method according to the invention has better transferability.

Therefore, the behavior of the deposits in the generator is improved and the formation of bridges and conduits is avoided.

These increase the amount of dust emitted during the gasification process, making the operation of the generator uneconomical.

The combination of high-pressure steaming and high-pressure degassing/gasification can also be solved by having the functions of a coal box and high-pressure steaming performed by a single, so to speak, enlarged coal box.

In this case, high-pressure steaming is discontinuous, just like charcoal box work.
Implement this.

According to the invention, several coal chambers and high-pressure steaming vessels are attached to the degassing/gasification reactor and these are alternately supplied with pre-dehydrated high-pressure lignite to the reactor.

In this variant, the drawbacks of discontinuities and increased thermal energy demand do not have to be taken into consideration for uniform sediment movement in the steaming chamber. Separation of steaming water is no longer a problem, and high-pressure steaming is replaced by high-pressure degassing and gasification. This is compensated for by the fact that it can be carried out at higher and possibly lower pressures.

When extremely dry fuel is required for high-pressure degassing and gasification processes, finishing drying can be carried out using superheated steam in which a portion of the high-pressure steaming is performed using saturated steam.

In order to accelerate the dehydration process, even in this modification, the amount of residual saturated steam can be increased during the steaming process.

This increases the velocity of water vapor passing through the lignite pile and therefore improves the heat transfer to the lignite.

The discharged residual steam containing CO2 is used as a gasification agent in the same way as the discharged water vapor in the final drying using superheated steam following high-pressure steaming.

It has also not been recognized heretofore that the high temperature crude gas with a high water vapor content which comes out of the high pressure degassing/gasification process can be extremely advantageously used as a high pressure cooking agent.

The crude gas in fixed-bed high-pressure gasification has an extremely high water vapor partial pressure at the reactor outlet after its saturation, and when soft lignite is used, it is several times higher than the gas partial pressure.

Therefore, the crude gas, after being saturated with water vapor and removing dust and condensed hydrocarbons, still has the high temperature necessary to carry out the cooking process.

Utilization of the crude gas from the high-pressure degassing/gasification process can further simplify the combined high-pressure steaming-high-pressure degassing/gasification method.

Crude lignite, especially soft lignite, is placed in a high-pressure vessel, where it is subjected to high-pressure steaming, degassing, and gasification.

The crude gas produced by the partial oxidation of the charcoal in a fixed bed in the lower part of the vessel flows upward in countercurrent to the charcoal, and undergoes degassing finishing drying and high-pressure steaming in various zones constituted, and is then discharged from the top of the high-pressure vessel to the outside. go out to

Water dripping from the crude lignite during high-pressure steaming saturates the crude gas rising from the finish drying zone.

However, during high-pressure steaming, especially when using soft brown coal, the amount of water released from the crude brown coal is generally greater than the amount of water required for crude gas saturation.

Depending on the selected operating parameters, a portion of this excess water is conducted out of the high-pressure vessel together with the crude gas in the form of a mist.

The remainder reaches the finish drying zone and degassing zone where it absorbs heat and evaporates.

Houyu leads to increased consumption of gasifier and fuel.

This can be prevented by incorporating a water-separator between the high-pressure steaming zone and the final drying zone.

At the same time as they are used, the steaming water which is returned to the circulation can be sprayed onto the top of the high-pressure vessel, thus enhancing the removal of dust and accompanying crude gases generated during the steaming process.

The hydrocarbons that condense during the cooling of the raw gas during the cooking process improve the sediment movement within the cooking chamber, so that the formation of unfavorable bridging and conduits can also be counteracted in the area of stone lines.

Only a small portion of the water vapor contained in the crude gas condenses during high-pressure steaming, resulting in only slight cooling of the crude gas.

Therefore, as is already known, it is possible and advantageous to utilize the crude gas coming out of the reactor for generating waste heat steam.

The heat demand for pre-drying of crude lignite in the high-pressure steaming zone is only 550-65 kg per 2 of the water separated in steaming when the heat of the steaming water is used to preheat the coking coal to 363 K.
Only 0 KJ, this amount of heat is extracted from the waste heat steam generation by means of the crude gas.

Therefore, the use of high pressure steam can be omitted.

This recognition characterizes the high value of the proposal to utilize crude gas for high-pressure steaming.

The comparatively extremely low heat demand for drying coal means that no additional heat loss occurs due to the high-temperature lignite or the high-temperature condensed water generated during high-pressure steaming in the high-pressure degassing/gasification method combined with high-pressure steaming. caused by

Another essential feature of the idea of the invention is that a mixture of water vapor and the gaseous components of the crude gas flows strongly through the lignite pile to be high-pressure steamed, thereby increasing the heating rate of the lignite, the chemical process of carbonization, and the discharge of the generated gaseous components. , therefore also polar liquid (ly opol
ar) and the entire capillary water separation process is accelerated.

These advantages also appear when using high-temperature, steam-containing, especially phenol-free crude gases produced in other processes by partial fuel oxidation, and when dehydrated coal is depressurized after high-pressure steaming for further use. Significantly effective.

Since only a small portion of the water vapor contained in the crude gas is required for the high-pressure cooking process, it is possible to use only a partial stream of the crude gas resulting from the combined casing process for the high-pressure cooking process. It is possible.

At that time, the crude gas has a water vapor partial pressure of 0.5 MP during high-pressure steaming.
Must not be less than a.

It is already known per se to use only a partial stream of the crude gas generated for degassing and final drying of the fuel.

In this process, so-called dry distillation gas is generated, and the remainder of the gas obtained by gasification is drawn off as tar-free, so-called clean gas.

When soft lignite is used, this dry distilled gas has less dust, while the clean gas has a larger amount of accompanying dust.

The division of the crude gas generated into these two substreams also makes it possible to utilize adjustable heating rates in the final drying zone and in the degassing zone, as is also known per se.

This is particularly advantageous for careful bilayer treatment of the fuel in the degassing zone.

Due to its low dust content, dry distillation gas can be advantageously used in high-pressure steaming, in which case it is introduced into the steaming zone through saturated garden stones after it has passed through the degassing zone and final drying zone, and generally removes the lignite pile from below to the top. flows to.

If only clean gas is used for high-pressure steaming, this clean scum can be drawn out of the reduction zone at high enough temperatures to be free of phenol;
Therefore, an advantage is recognized that the generated steaming water does not become a load on the dephenolization device.

The clean gas withdrawn in this case should only be introduced into the boiling chamber above the lignite pile after it has been cleared of dust and saturated with water.

When a common high-pressure container is used for the high-pressure steaming process and the scum removal/scalping process, a gas outlet is provided between the high-pressure steaming area and the final drying area.

If the dry distillation gas and the clean gas are drawn off separately, the two gas streams can be combined again for high-pressure cooking.

In this case, it is expedient to dedust the clean gas prior to the merger or to dedust the gas mixture after the merger and saturate it with steaming water.

In order to accelerate the dehydration process during high-pressure steaming, the crude gas or the gas in the partial stream can be heated and introduced into the high-pressure steaming chamber.

Alternatively, the crude gas partial stream can be brought to such a high temperature that the accompanying phenol is destroyed and saturated with water before being used for high-pressure steaming.

By very careful drying and degassing of the crude lignite according to the method according to the invention, it is also possible to draw out abrasion-resistant coke that does not disintegrate after high-grade degassing.

In order to produce a solid fuel with little smoke, degassing, final drying and, if necessary, subsequent high-pressure steaming are carried out separately from high-pressure gasification using a high-temperature scavenging gas with as high a water vapor content as possible.

The degassed fuel can then be cooled and depressurized and used as coke.

The resulting coke or its substreams can be used for high-pressure gasification carried out in a separate chamber, the resulting high-pressure gas or its substreams being used for degassing, finishing drying and high-pressure cooking.

The present invention will now be described in detail with reference to four embodiments.

[Example 1] Crude lignite having a particle size of 5-60 and a moisture content of 57% and a temperature of about 293°C is fed into a bunker and heated to about 363K with steam and, if necessary, sprinkled with pure water.

From there, the crude lignite reaches the coal box chamber and is discontinuously pressurized to 2.5
It is pressurized to MPa and sent to a container for crude lignite pressure steaming.

In the coal box chamber, further preheating of the crude lignite to 393-493° C. takes place by means of a partial flow of cooking agent or by steaming water at a temperature of about 490° C.

Steam at a temperature of 495°C is fed into the high pressure steamer above the lignite pile.

At this temperature of the steaming agent, crude lignite can be dehydrated to about 25% H2O in a steaming time of 60-90 minutes.

Since the crude lignite is only dehydrated to about 35% residual water, the steaming time can be reduced to 30-40 minutes.

The high pressure steamer can thus be kept relatively small.

The water dripping from the lignite and condensing from the cooking agent is separated by suitable devices in the steamer.

In this case, the water entrains the generated fine particles. This cleaning effect is enhanced by distributing circulating hot steaming water into the steamer.

The dehydrated coal is uniformly heated to 470-500 K and continuously sent to the same pressure drying, degassing and gasification high pressure vessel at the same <2.5 MPa pressure.

Compared to the commonly used fuel of about 303K and 20% H2O, an extra heat of about 370KJ per Kt of dry coal (H2020%) is sent to the degassing/gasifier along with the high-pressure steamed lignite.

This heat is sufficient to dry the charcoal from about 35% to about 20% H2O without removing heat from the degassing/gasification process.

At that time, about 81% of the brown coal is dried by the heat of high-pressure steaming, of which about 66% is in liquid form in the high-pressure steamer, and about 15% is dried by the heat of high-pressure steaming.
is carried out by evaporation in the high pressure degassing and gasification reactor and about 19% by thermal evaporation from the high pressure degassing and cassification process.

The lignite pieces are heated evenly and reach the degassing/gasifier without any difference in the latent water content and without hardening due to the influence of the air atmosphere on the particle surface, where the pressure is 2.5 MPa (slightly lower than the standard atmosphere). Since the final drying is carried out with a steam volume of approximately 1/21), this drying takes place without appreciable damage to the lignite particles.

The generated hot steam of about 373°C and also hot water serve to heat the charged coking coal to about 363K.

Steam at 2.5 MPa and saturated at about 495° C. is used as the steaming agent.

If the available steam is at a higher pressure and temperature, it is depressurized and saturated with steamed water before entering the steamer.

The heat demand in the steamer is 1100 K per KP of water released.
It is J.

When steam is introduced, a small amount of residual steam is always used for high-pressure carbonization (Dr.
It is adjusted so that it flows into the degassing/gasifier together with the CO2 produced during the uckinkohlung.

The steaming water produced has extremely low phenol content.

[Example 2] Crude lignite having a grain size of 5-65-6O and a moisture content of up to 57% is hydraulically sent to a bunker for a gasifier using steaming water at a temperature of 370°C, which has been reduced to atmospheric pressure, and preheated to 363K at the time. .

From the bunker, it passes through a coal box chamber and reaches a large high-pressure vessel, at the bottom of which the lignite is gasified in a fixed bed at a pressure of 2.5 MPa.

The generated gas flows upward in countercurrent to the brown coal.

Inside the vessel, an ash area, an oxidation area, a reduction area, a degassing area, a finish drying area, and a steaming area are formed in sequence.

Water dripping from the crude lignite in the high pressure steaming zone saturates and supersaturates the rising crude gas, causing TfJ (fog generation).

Excess boiling water reaches the shoulder line and takes away the necessary heat from it due to its evaporation.

The evaporation of the steaming water may lead to disadvantages such as an increased demand for oxygen and fuel, a worsening of the cassification steam cracking and an increased C02 content in the crude gas.

When the proportion of excess water is large, these drawbacks can be avoided by incorporating a device for separating high-pressure water from lignite between the high-pressure steaming zone and the final drying zone.

Along with the separated steaming water, part of the fine dust generated during steaming and accompanying gasification gas is carried away.

The steaming water is depressurized and used for hydraulically transporting the coking coal to the bangka.

The soft lignite is dehydrated in the steaming chamber to a water content of approximately 35%.
Finish drying, degassing, and gasification are performed in each area of the shoulder line.

The crude gas exits at the top of the high-pressure vessel and reaches the waste heat steam generator.

In this example, the crude gas saturated with water vapor at about 2.5 MPa1 from the degassing/gasification process of the fixed bed high pressure gasification serves as the cooking agent.

The saturated crude gas has a water content of 1.6 per N m8? It is.

The heat demand in the steaming zone is approximately 580 KJ per 2 of the separated water.
It is.

The crude gas of the steamer has a water content of about 1.3 KP/Nm3 and a temperature of about 468 °C.

The waste heat steam generation (0.5 MPa steam) is limited by the heat released by the hot raw gas during steaming with the raw gas.

The crude gas flows continuously through the lignite pile, thus ensuring rapid heating of the lignite and immediate CO2 emission.

This shortens the cooking time.

Hydrocarbons condensing from the crude gas improve sediment movement.

In this embodiment, the discharged steaming water contains a large amount of phenol, and it may be disadvantageous to increase the load on the dephenolization device by about 50%.

It can be seen from the variation of the raw gas parameters in the steaming zone that only a small portion of the water vapor contained in the raw gas is required for high pressure steaming.

Therefore only a partial stream of the crude gas can be used for cooking,
The following variants appear in this case: 1. Withdrawing hot clean gas free of tar and phenol from the reduction zone of the fixed-bed high-pressure gasification.

The clean sludge is saturated with water, dusted as necessary, and then introduced into a high-pressure vessel above the lignite pile for high-pressure steaming.

This flows through the steaming zone in the direction of the lignite path and exits the high-pressure vessel between the high-ratio steaming zone and the final drying zone together with the separately led dry distillation gas. ○No increase in load on the dephenolization equipment due to steaming water occurs. .

2. When dust-free dry distilled gas is used for high-pressure steaming, it flows directly in countercurrent to the lignite path from the finishing drying zone to the high-pressure steaming zone, where it is saturated with steaming water and flows from the high-pressure steaming zone above the lignite pile. get out.

Steamed water contains a lot of phenol. The condensed hydrocarbons improve the movement of the sediment and some are discharged along with the fine dust washed out by the steaming water flowing away.

[Example 3] In this example, crude lignite with a grain size of 5-12 mm and a water content of up to 57% is preheated to 363 K and fed from a bunker alternately into two high-pressure vessels.

Both high-pressure vessels are tasked with the following tasks in chronological order: receiving unpressurized lignite, pressurizing coking coal to 10 MPa with steam, and pressurizing coking coal to 10 MPa at 583 K in 15 minutes.
The lignite is dehydrated by high-pressure steaming to a maximum of 100%, and the steamed water is separated.The pressure is reduced to a degasser of 2.5 MPa installed under the high-pressure container, and the lignite is sent to the descaling device.

Both high-pressure vessels alternately supply fuel to the high-pressure degassing section.In the degasser, scavenging gas produced by fluidized bed high-pressure gasification is supplied.
Careful final drying and removal of scum are carried out.

The coke produced here is quantified and subjected to the fluidized bed gasification process.

After dust is removed from the generated scum to utilize sensible heat and latent heat, some of it is led to the removal process as scavenging scum, and some of it is used to utilize exhaust heat.

[Example 4] In the implementation side drug 4, crude lignite with a particle size of 40-60 mm and a water content of up to 58% was heated to 363 K in a bunker and sent to coal box chambers (multiple).

Pressurize with hot water and grind alternately with one high-pressure water stream of 3 MPa and 500 mm.

It is sent to a high-pressure steamer using high-pressure water and is pre-dehydrated to a water content of 48% during hydraulic transport.

In the high-pressure steamer the lignite is separated from the transportation liquid; 2.
It is finished steamed to a water content of 35% using saturated steam at 5 MPa.

The steaming water flows off with the transport liquid at a temperature of about 485°C.

A partial stream containing fine particles is separated from this hot water using a hydrocyclone.

The supernatant from the hydrocyclone is brought to a pressure of 3 MPa and 503 again via a pressure booster pump and a heat exchanger, and is again used for hydraulically transporting coking coal.

The lignite pre-dried to a water content of 35% passes from the high-pressure steamer to the high-pressure degasser where it is thoroughly dried with scavenging gas and degassed to a temperature of 100K.

The coke produced is cooled, decompressed, and recovered as low-smoke fuel.

Claims (1)

[Scope of Claims] 1. In a high-pressure degassing/gasification method for coarse brown coal, especially soft brown coal, granular coarse brown coal is placed in a high-pressure steaming chamber with a pressure higher than IMPa, where it is partially dehydrated and high-pressure carbonized using a steaming agent, The coal thus pretreated is subjected to uniform shrinkage and uniformly heated to a higher temperature by 423 without reducing the pressure below the pressure in the high-pressure degassing and gasification chamber, and also at 0.
, without reducing the pressure to below 5 MPa and without cooling the lignite to a lower temperature than 423, to the degassing and gasification chamber, where the lignite is further thoroughly dried due to its high heat capacity; A method characterized by subsequent high-pressure degassing and high-pressure gasification. 2. The high-pressure steaming chamber is always at the same pressure as the high-pressure degassing/gasification chamber, and the pretreated coal continuously reaches the high-pressure degassing/gasification chamber from the high-pressure steaming chamber. The method described in Section 1. 3 The high-pressure steaming chamber has a higher pressure than the degassing/gasification chamber during high-pressure steaming, but even if the pressure is lower, at least IMP
The pressure higher than a is maintained, and after pre-treatment of lignite, the pressure in the high-pressure steaming chamber is reduced to the pressure in the degassing/gasification chamber,
2. A method as claimed in claim 1, characterized in that the lignite reaches the degassing and gasification chamber discontinuously. 4 High-pressure steaming is carried out in one or several chambers in which lignite is simultaneously charged from an unpressurized bunker into a degassing/gasification chamber under high pressure. Reducing the pressure to atmospheric pressure, receiving crude lignite, pressurizing it to vaporization pressure, high-pressure steaming and water separation, pressure balancing with the high-pressure degassing/gasification chamber, and degassing/gasification chamber for partially dehydrated lignite. 4. A method according to claim 1 or 3, characterized in that the discharge is carried out in the following manner. 5. The method according to claim 1 or 4, wherein the lignite that has been preliminarily dehydrated by high-pressure steaming is subjected to final drying using heated steam. 6. A patent characterized in that the residual steam leaving the lignite pile during high-pressure steaming, along with the extracted CO2, and the steam flowing out when finishing and drying the lignite with superheated steam can be used as a casing agent. A method according to any one of claims 1, 4 and 5. γ The method according to claim 1 or 2, characterized in that high-pressure steaming and high-pressure degassing/gasification are performed in a common high-pressure vessel. 8 The water dripping from the brown coal in the steaming chamber washes away the tiny particles generated from the brown coal, and the water removed by steaming is returned to the circulation and sprinkled above the brown coal pile in the steaming chamber to enhance this cleaning effect. A method according to any one of claims 1 to 1, characterized in that: 9 The water removed during steaming is continuously separated in the steaming chamber,
The method according to any one of claims 1 to 8, characterized in that the steam and/or hot water is sent to the production of steam or hot water. 10. The method according to claim 1, wherein the method is used for preheating crude lignite. 11. Claims 1 to 11, characterized in that the depressurized hot water is used to preheat the crude brown coal at the same time as hydraulically transporting the crude brown coal to a bunker provided before the method. Any of the methods described in 0-12 is characterized in that the steaming water separated under high pressure is used for hydraulic transport of lignite from the coal box chamber to the high-pressure steaming chamber, in which case preliminary steaming of the lignite has already been carried out. The method according to any one of claims 1 to 3 and 7 to 9. 13 The crude lignite in the coal box chamber is heated by a partial flow of the cooking agent and/or
or Claims 1 to 3, 7 to 10, and 1, characterized in that they are preheated by high-temperature steaming water.
2. Any of the methods described in item 2. 14. A method according to any one of claims 1 to 13, characterized in that saturated, optionally slightly heated, steam is introduced into the steaming chamber for high-pressure steaming. 15. The steaming agent is steam saturated with steaming water at the selected steaming pressure, in such an amount that a small amount of residual steam always flows into the degassing/gasification chamber together with the gases produced during the carbonization of the brown coal. 15. A method according to any one of claims 1 to 14, characterized in that the lignite is introduced above a pile of lignite in the steaming chamber. 16. The method according to any one of claims 1 and 2 and claims 7 to 15, characterized in that water vapor generated within the water canopy of the high-pressure degassing/gasification chamber is used for high-pressure steaming. 17 High-pressure steaming of granular crude lignite is carried out under high pressure with a steam partial pressure higher than IMPa using hot, saturated or slightly superheated steam-containing gas from partial oxidation of the fuel, and the steam-containing hot gas is dehydrated. The steam that accompanies the gas during high-pressure steaming has a steam partial pressure of 0.
It is characterized in that it condenses in an amount not less than 5 MPa, and the water vapor-containing gas leads both the gases generated during high-pressure steaming out of the high-pressure steaming chamber, promoting the process of polar liquid and capillary water separation. A method according to any one of claims 1 to 13. 18 High-pressure steaming, sufficient finishing drying, degassing, and gasification are performed in a high-pressure vessel, and the coarse scum produced by high-pressure scum at the bottom of the vessel flows upward in countercurrent to the lignite, and at this time, it flows upward in the lignite pile. The method according to any one of claims 1, 2, 1, and 1[gamma], characterized in that descaling, sufficient final drying, and high-pressure steaming are carried out in a region where these directly transition to each other. 19 Claims 1, 2, and γ, characterized in that a part of the water separated during high-pressure steaming of crude lignite is guided out of the high-pressure vessel by coarse scum in the form of fine droplets. , the method according to any one of items 11 and 18. 20 Claims 1, 2, 1 to 13, and 17 to 19, characterized in that dripping water is separated between the evaporation zone and the final drying zone by an appropriate device. Any of the following methods. 21. The method according to claim 1γ, characterized in that the steam-containing gas of the partial fuel oxidation is saturated before being introduced into the steaming chamber to remove accompanying dust and condensed hydrocarbons. Claims 17 to 20, characterized in that the hydrocarbons condensed during the steaming process and during cooling of the steam-containing gas have a beneficial effect on the sediment movement of the lignite to be dehydrated. Any of the methods described above. 23 The steam-containing crude gas used in high-pressure steaming is saturated with water separated from lignite during high-pressure steaming,
Claim 11 characterized in that dust is removed.
24. When using high temperature steam-containing gases for partial oxidation of fuels that do not contain phenol, and when using superheated steam-containing gases, these are introduced above the lignite pile in the steaming chamber. The method according to any one of claims 17 and 19 to 23, characterized in that: 25 In the degassing/gasification chamber, the particles that have been pre-dehydrated by high-pressure steaming are further carefully dried and degassed.
26. Method according to any one of claims 11 to 20, characterized in that only a partial stream of the crude gas produced in the degassing and gasification chamber is used. 26. Careful final drying and degassing. Claims 17 to 20, 22, characterized in that the gas partial stream with a low dust content and high in hydrocarbons used for the high-pressure steaming of the coking coal particles is
, the method according to any one of items 23 and 25. 21. A partial stream of the crude gas produced in the degassing and gasification chamber is withdrawn from the reduction zone as tar-free clean gas and subsequently used, after saturation and, if necessary, dust removal, for the high-pressure steaming of the crude lignite. Claim 1 characterized in that
7. The method according to any one of items 19 to 21 and 23 to 24. 28. The clean gas is withdrawn from the reduction zone at such a temperature that the water vapor associated with the gas is free of phenol prior to its introduction into the cooking zone, or the source gas substream is also brought to such a temperature. The method according to any one of claims 17, 19 to 20, 23 to 24, and 2[gamma], characterized in that: 29. After high-pressure steaming of the granular coarse lignite using the hot steam-containing gas of fuel partial oxidation, the dewatered particles are depressurized and then used for further use if necessary. The method according to any one of items 19, 21 to 24, and 26 to 28. 30 Claims 1 to 6, and 8, characterized in that the high-pressure gasification process is carried out separately by a quantitative feeding device or in a container separated from the high-pressure steaming, final drying, and degassing processes. 17th to 17th, 19th to 21st, 2nd
3. The method according to any one of items 24, 21, and 28. 31. Claims Nos. 1 to 6, 8 to 17, characterized in that the coke obtained after the high-pressure degasification process is cooled and depressurized, and recovered as fuel with little smoke. 19th to 21st, 23rd, 24th, 27th. The method according to any one of items 28 and 30. 32 Characterized by the fact that the coke obtained or only a part thereof undergoes high-pressure gasification carried out separately, and the gas or partial stream produced here is then used as scavenging gas in the degassing, final drying and high-pressure steaming sections. The method according to any one of claims 1 to 6, 8 to 1 γ, 19 to 21, 23, 24, 2 γ, 28, 30, and 31. 33. Claims 1 to 6, 8 to 17, characterized in that in high-pressure steaming, part of the ash content is removed from the lignite, so that the resulting coke has a relatively low ash content.
, 19th to 21st, 23rd, 24th, 27th, 28th
and the method according to any one of items 30 to 32.